Field of the Invention
The present invention relates to Quality of Service (QoS) realization in an IP network, and more particularly, to a method for realizing QoS in IP flows based on at least one predefined or currently used field.
Description of the Related Art
In current IP networks, applications may specify the level of QoS that is associated with each IP packet flow. Different applicants may require different levels of QoS. For example, a voice application requires low delay while a file transfer application does not. In addition, different packets of one application may also require different levels of QoS. For example, in one video application, packets for a full picture require higher error tolerance than packets for the difference of succeeding pictures. If there are several IP flows, i.e., IP packets that have the same source IP address, destination IP address, Layer 4 protocol number, source port number, destination port number and Differentiated Services Code Point (DSCP) for DiffServ, which require the same level of QoS, it is necessary to classify them into the same Layer 2 (L2) service requirements. For example, the usual web browsers typically establish several TCP connections simultaneously, for data with the same level of QoS, for speeding up the connection. However, these current web browsers do not use these simultaneous connections to separate the packets in L2. It should be noted that the DSCP field associated with each IP packet is a field that is used to specify the DiffServ treatment, and as such, the DSCP field is excepted to include priority/urgency equivalent information.
In prior techniques, it is assumed that each IP FLOW, which is detected, for example, by an entity between a user equipment and a core network in a Universal Mobile Telecommunications System (UMTS), is a single IP flow. Upon detection of each IP flow by the entity, a logical channel is generated for the IP flow and the IP flow is mapped to a corresponding logical channel of a MAC layer. In current IP networks, for each logical channel that is generated, a separate MAC queue is also generated. Thus, all IP flows are treated in different MAC queues, even if the IP flows have the same level of QoS requirements. While in this implementation, IP packets with the same QoS requirements may be treated in the same manner, this implementation is not efficient in terms of MAC queue management. In addition, because this scheme uses a different logical channel flow identifier for each IP flow, a longer logical channel flow identifier is required. The longer logical channel flow identifier is not desirable because the logical channel flow identifier needs to be transmitted over the air.
If logical channels requiring the same level of QoS are multiplexed before the MAC queuing process, the inefficient queue management may be avoided. However, this implementation does not solve the issue of the longer logical channel flow identifier, as outlined above.
In one technique, the MAC can also concatenate packets from different logical channels with the same QoS requirements. In this case, all MAC segments, which are components of MAC packet data unit (PDU), need to have logical channel flow identifier information. This technique makes the PDU structure more complicated and inefficient. In addition, because this scheme uses different logical channel flow identifiers, this implementation also does not solve the issue of the longer logical channel flow identifier, as outlined above.
In currently used techniques, if different applications require different levels of QoS, additional information will need to be passed when each IP packet is padded to the MAC layer. To use layer 1 (L1)/Layer 2 (L2) resources in IP networks efficiently in support of diverse QoS, it is important to classify IP packets into different L2 service requirements.